Triggernometry – Choose Your Weapon! Part I

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by Jim Higginbotham
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Choose Your Weapon! Part I


“What handgun would you recommend for self defense?”

S&W M-66 .357 Magnum
Accuracy – 1.75 “
Controllability Index – 11.6
Effectiveness Index – 127% (TKO)

That is a question I get a lot. Sometimes it is from folks who have little or no shooting experience and sometimes it is from folks who just want me to tell them that the latest weapon they have chosen wasn’t a really stupid choice.

Friends, I don’t have an ambiguous bone in my body but I cannot give you an answer without more input. Even then I don’t usually make specific make and model recommendations for I cannot know the totality of your circumstances or, without spending at least a day on the range with you, your skill level. It is truly a case of the Biblical admonition to “work out your own salvation”. All I can do is report on what you might expect to find, but you will have to go shoot the guns and do more study on your own in order to make an informed decision.

An uninformed decision could result in disaster. What works for some pundit or national champion may not be the gun that works for you! I can think of few more suspect pieces of equipment to purchase than a gun (of any type) if you don’t know how to use it. An automobile comes to mind. Without a modicum of skill, both are a catastrophe looking for a place to happen.

This is an overview of a simple screening process I have adopted over the years. There are much more involved tests one can do – indeed I do them myself – but I am assuming that if you were a full time shooter you will have developed your own. My goal here is to simplify.

What are we looking for in a defensive handgun? Simply put we are looking for one that is

  1. reliable,
  2. accurate enough to do the job (in our hands),
  3. holds enough bullets,
  4. strikes a reasonable blow,
  5. can be recharged after the fight expeditiously
  6. can be carried on the person daily, and
  7. you can get it into action quickly from your preferred mode of carry.


There may be other features you might find important as well, but even with these simple criteria there are still enough handguns out there to confuse you to the point of indecision, which is the worst outcome because it leaves you unarmed and maybe even still playing video games.

Glock 19- 9mm
Accuracy – 2.9 “
Controllability Index – 4.9 (less flyer=9.8)
Effectiveness Index – 100% (TKO)

Here is the first half of what I think that screening process to help you assess the qualities of those handguns you might be considering. My basic approach is to go shoot the guns. Your answer to that may be “how the heck am I supposed to do that??” but not to worry. Lots of indoor shooting ranges have rental guns, and the nice thing about them is that the gun has generally already been broken in from heavy use. Also, if you have friends who shoot they will most likely be happy to take you shooting with their guns as well, especially if you buy the ammo.

The downside of this approach is that you will be limited to a few types of guns, shutting off many potential candidates for your consideration. But remember, the ranges rent Sigs, Berettas, Smiths and Glocks for a reason. They run and they break down less frequently than “el cheapo” equipment. This is something to consider when you are first starting out. And even if you elect to buy something less mainstream or something that looks like the same gun for less money, you will have a reliable baseline from which to measure you new potential acquisition.


Obviously a defensive firearm must work to be effective. Nothing mechanical works every time. But quality handguns today work nearly every time. The fly in the soup is the operator. He/she can cause malfunctions. I recently selected 9 “dash cam” videos involving police officer shootings and discovered what even to me were shocking results. Of the 9, 45% of the police officers involved experienced a malfunction of one sort or another! Fortunately most had cover and were uninjured, but the one who did not and almost lost his life to a subject he had already shot once, center mass with no effect!

Surprisingly most of these “malfunctions” where with a firearm design that many recreational shooters and “frequent forum flyers” think is faultless when it comes to reliability.

Nothing is faultless.

Remington Rand 1911a1 1943
Accuracy – 1.4 “
Controllability Index – 19.6
Effectiveness Index – 180% (TKO)

If you think that revolvers work all the time then you have not shot enough! Some 30 years ago, an acquaintance lost his life when his brand name .357 Magnum locked up in a gunfight. It had been fired a good bit but never with his duty ammunition before that day! That can be, and was, a fatal mistake.

The only way to tell if a weapon is reliable in your hands is to shoot it! It does not matter if it works in other people’s hands or got a great review in the cover story of your favorite gun magazine. At least some of the time, shoot the ammo you plan to carry. It will do you no good to run your reliability tests with weak .38 Wadcutters if you intend to carry magnums that will jar the fillings out of your teeth!

Break In. Every gun needs and deserves a break in period, even a wheel gun. The consensus seems to be 200 rounds and I don’t disagree with that, though I have seen some guns that worked in the first 200 rounds develop a case of the ballistic hiccups later – so keep an eye out.

This is a pass/fail test. I won’t accept a gun that regularly malfunctions. Sometimes it is an ammunition or magazine issue and it can be fixed. But never trust your life into the hands of a gun that works “most of the time,” because if you follow Murphy’s Law, when you need it in a gunfight, it won’t.


As we discussed in our last column, many folks are a whole lot more casual about where they hit than I would prefer. I can cite you dozens of cases where shooting a subject “center mass” with a magnum round was not good enough to end the fight in a timely manner. On the other hand, I cannot cite any cases where a .22 LR to the tear duct has failed to stop (to the temple Is another matter entirely). The problem of course is hitting under pressure during the dynamics of a real street fight.

My standards for accuracy may not be what be what you are accustomed to. I feel that the physical accuracy of a gun is almost a given these days. There are so many fine pistols and revolvers on the market that will shoot into a ragged hole that you need not worry about the percentage of an inch difference between any two.

S&W M-15 2” – .38 +P
Accuracy – 2.1”
Controllability Index –10.2
Effectiveness Index – 101% (TKO)

The true accuracy of a handgun can only be judged by firing as you would in a gunfight. If it is a Double Action Revolver, you test it in double action, standing, freestyle, without a rest, in any “stance” you prefer. If it is Double Action/Single Action (like a Beretta 92F, Sig 226, etc.), it should be fired in that order, the first pull long and the subsequent short. If it is a Glock or an XD then all trigger pulls are consistent. For now we will not limit time, but you may have to practice in order to meet my specifications with any gun, taking as much time to shoot as you need. If you can’t shoot your gun into the these specifications you are not prepared to be in a gunfight, no matter how mechanically accurate your firearm may be.

I use a 2.5 X 4” target area at 10 yards on our training target but a good practical substitute might be a 3X5 index card, placed horizontally. 5 hits out of 5 shots on the card will suffice. This is a pass or fail test. If the gun passes, or more than one gun passes, it qualifies as worthy of being the gun that defends your life. If not, not. Measuring groups is fine, 3″ or less will do. If the miss is your fault, then do it over. Successful results will be repeatable. In preliminary screening I tend to use the group size (since you may be able to change the sights later) but in the final test, only hits count.

For the record I do test guns from a bench rest. But it is only my “serious” handguns, and they eventually get tested at 100 yards. I feel that for a gun you plan to carry every day you have to start with the basics, and the basics are if you can reasonably hit your target with the gun at normal gunfight ranges. Ergonomics and how the gun fits you will have more to do with hitting your target than the mechanical accuracy of the gun.


Group size (accuracy) is only 1/3 the equation of marksmanship. We need to measure how rapidly we can obtain those desirable repeat hits and how hard they hit. That last is for later. You have to test the guns and loads yourself. No one can tell you how many rounds it will take to end your gunfight, but I practice with five. This is mostly because of the research of Ed McGivern. If you don’t know the name look him up, it is worth the trip.

Ed developed what can only be termed extreme skill at shooting accurately and rapidly. His standard, which he exceeded regularly, was a “hand sized group”. If you put your hand over your heart you will find it covers the width and height of the sternum just about perfectly. Not a bad “standard” for dimensions that you should try to effectively shoot into.

For simplicity’s sake I just use 5” as a standard. If you want an easy target you can fold a sheet of copy paper in half – that makes it 8.5” X 5.5” which is just about covered by the hand with the fingers splayed (Ed kept his more or less closed). Range will be 5 yards. Why? Because that is probably about average for gunfights and it is, coincidentally, what Ed McGivern used.

It is also a good way to keep track of your improvement. Shot timers are much more prevalent today and easily obtained. A good one can be had from Pact: Another option, if you are not technologically challenged like me, is an “ap” for an iPhone which converts it to an excellent timer. I think it may be free. If not it does not cost much. A shot timer “listens” for the first shot and last shot in your string and times them perfectly. It is much more effective than trying to nail it with a stop watch and is a great investment for anyone serious about improving their shooting.

Please understand we are not talking about competition here. We are not trying to match the likes of Jarrett, Letham, et all, fantastic shots that they are. We want to know what we can do. We want to know which gun we shoot better, because our life might depend on that choice. There are so many factors that can effect that outcome of your gunfight and accuracy is only one of them. But if all the other factors go in your favor, are you willing to let your accuracy rely on you having a “lucky day?”

If you are in a gunfight, it is already NOT your lucky day!

For each gun that you wish to test your ability to shoot with, record the size of the group of 5 rounds fired as fast as you can shoot them with reasonable accuracy and record the total time it takes you to fire those 5 rounds from the first shot to the last shot with the timer (or a stopwatch if it is all you have).

Now take pen and paper – or the calculator on your iPhone – and divide the number 50 (an arbitrary “par”) by the size group, then the number of seconds, to the tenth, it took to fire it.

Example, you shot a 5” group in 1 second – which is pretty good. 50/5/1 = 10. That is your “Controllability Index”. 10 would be an excellent score. 5 would not be horrible. Compare one gun to the next, not your performance to your buddy’s performance. This is about you, and it is the guns that are competing, not you. Keep notes. Gauge your progress.

Here is another even simpler formula if that one sounds too confusing. Use the same target size paper. Record the total time and add one second penalty for every shot that is outside the group or target.

You might ask why I suggest about 5 inches and not 8 or 10 like many competitions and training standards. Because the target and you are standing still in this test and the target is not shooting back. Don’t expect to do as well on the “two way range” as you do on a casual day on the public or private shooting range – indeed a 50% deterioration would be optimistic for any of us. 1 to 1.5 seconds is good (really good), 2 seconds is probably good enough (remember we are not measuring reaction time or draw speed here just the shooting). More than 2.5 to 3 and you should really seek some training, unless, like me you are old and feeble. Remember Ed? His best time was 4/10ths of a second. In 9/20ths of a second he put 5 bullets in one hole at 5 yards!!!!!! That’s with a revolver! I’m still working on that one.


You knew we would get to this. Sad to say I am not the one to cut through all the smoke and mirrors of how to measure the “power” of handguns. I have studied it for over 4 decades and the more I learn the less I know.

What I offer here is not THE answer, it is AN answer. There are others just as valid. We don’t have space here to explain fully all the nuances of how these various rating systems came about. I don’t claim that any one of them is better than any other – none of them are perfect! What is included below are comparisons based on the simplest forms of mathematical models. To be sure, we know that a .44 Magnum is more effective with a normal hit to the body than a .22. But mere fractions of an inch off the mark can change the whole picture. This is a topic for an entire article or maybe even an entire book! There is no benefit if I delve into an esoteric discussion of the effect of “hydrostatic shock”, the “WAVE theory” or shooting tons of 10% gelatin here. That is for another day … maybe… and maybe not. At the end of the day many theories about effectiveness in a gunfight are semantics, and there is plenty of information on the internet out there already if you choose to consider it valid. Opning about goat tests hasn’t gotten anyone to a definitive answer, and I don’t feel there is one when so many variables are in play in what will never be a definable environment. Every gunfight is different, period.

What I will do here is leave you to your own devices rather than try to convince you of “the one true way.” The easiest way I know is to pick a middle of the road cartridge, say the .38 Special or the 9mm auto, and compare it to what you are shooting in the test. What measure you use is up to you. I will use a standard 124 grain 9mm (Luger, Parabellum) traveling at 1104 feet per second, and you can plug that into whichever formula you decide to use. Not to endorse this particular round at all, I will use it as our 100% in the example. You can do this with whatever your “ideal” is, as your “100%.”

Most common probably is the IPSC/IDPA Power Factor. The formula is (bullet weight x velocity)/1000. For our 9mm, that works out to 137.

Be sure to include barrel length in your calculations, whether it be your 100% or your comparison cartridges. According to Ballistics by the Inch (, a 125gr Corbon .357 Magnum comes out of a 6″ barrel at 1715 fps., whereas it chronographs at 1257fts. from a 3″. These are not hard numbers due to variance is cylinder gap and whatnot, but it will give you an idea of the differences in power factor that barrel length can effect with many calibers.

Ok, back to our comparison. I am going to use the example of an 90gr. Corbon .380 DPX from a 3″ barrel at 1027fps. That works out to 92.43. (90×1027/1000). We then divide that by our “100%” 9mm example and it comes out to .67, or 67% as effective as the 9mm.

Here are a few more systems you can google and I will give you what our 9mm comes out to as a comparison.


  • Taylor Knock Out = bullet weight X velocity X diameter / 7000. (9mm = 7)
  • Hatcher Scale – a bit too complex for this article, but viable (9mm = 28)
  • Kinetic Energy* – The typical 9mm will go about 330 ft lbs.


You can even use what is referred to as “One Shot Stops” which mainly are compiled by my good and trusted friend Evan Marshall and his sidekick Ed Sanow. OSS numbers are not silly or wrong, as some imply. But they are not the definitive guide to what ends a gunfight. Evan Marshall’s statement on the matter is “OSS numbers are a measure, not a tactical reality. Shoot to slide lock, draw your next gun and repeat as needed!” Side lock is what happens when a semi-automatic pistol is empty. The slide locks.

Don’t confuse One Shot Stops numbers with a probability of ending a fight with one shot…there is a lot more to it than that! The .357 Magnum can be expected to stop a fight within 5 seconds with a “center mass” hit about 1 time in 3 (OSS numbers filter out multiple shot failures!). Don’t get killed for a lack of understanding Simply use the rating of the load under test divided by that of a typical 9mm or .38 load, at about 70%.

You could use the Wound Volume from the FBI lab test series, just pick the standard for the .38 or 9mm and use it as a modifier.

No endorsement or criticism is implied in the above systems or models. Choose your own system with which to measure the effectiveness. One exception; *Note – The one thing I do know is that Kinetic Energy is not a good measure of effectiveness. Entire books have been written covering that topic (amongst others).


So far we have covered some of the more important characteristics of handguns we might consider for defensive use. Next month we will cover other important topics. I should mention that there will be no “master number” assigned by combining all of these tests or characteristics. Your lifestyle and situation may change the emphasis on what one particular feature is more important than others. Super compactness may mean a lot to you and your requirements while another may live in a “target rich environment” where effectiveness is the prime consideration and he may be more likely to have to deal with multiple assailants. Those are decisions that must be left to the individual. Just mark down your assessments in each category and then rank them by importance to you…not me.

A word about the accompanying pictorial examples; They are for illustration only, the numbers mean only something to the people who shot them – the measures may change greatly in your hands. Also bear in mind you might be having a bad day on the range. Shoot the tests often, keep an average.

OK, we have reached a good spot for a break. Next month we will return, same time same channel, and finish up with other important factors like capacity, how to keep the gun running in a fight and considerations about the size of the weapon.

Happy trails ’til then!



{ 17 comments… add one }
  • David Grimes April 17, 2015, 10:56 pm

    Good stuff.

    I ran across the perfect mathematical definition of the proper carry caliber some time back and always try to share it.

    The proper caliber for your carry gun is the largest caliber that you will carry with you at all times.

    molon labe

  • David Grimes April 17, 2015, 10:29 pm

    Actually, a few months back, I ran into the perfect mathematical answer to the question “what is the proper carry caliber.”

    The answer is simple – –

    The proper carry caliber is the largest caliber that you will carry at all times.

  • Jerry October 13, 2011, 12:17 pm

    As a former fed firearms instructor for Special Agents; Troopers; and Police Detectives in various task forces, I think your article is good. I always recommend a revolver for the novice. Without some real training, folks forget things and problems result. Personally, my S&W 3913 with night sights and the extended magazine grip piece is my carry weapon. I use 9mm 147 grain sub-sonic hollow points. Let them know, that shot placement is the answer. Don’t panic; know your weapon; know your capabilities and know how to practice self-control. I am reading of too many shootings with 80 and 90 rounds fired with the perp getting hit 2 times. Use cover; in none, then concealment; get a sight picture (this is not a war zone – its main street USA with the folks we are protecting out there); and squeeze. Good job, waiting for part 2.

  • mstrong1 October 13, 2011, 9:29 am

    Oh, and part of my package, 100 rounds minimum at 5 yards, every week, with expert instruction when available.

  • mstrong1 October 13, 2011, 9:25 am

    My final choice for a tucked in shirt office guy like me is a J frame 340PD (ramp), Crimson Trace LG-405-P20 laser grip/shock absorber in a DiSantis Superfly pocket holster with Gold Dot .38+P short barrel HP’s (#23921), a couple speed strips and a Teddy Jacobson (Actions by T) trigger, chamfer & crown job. I TOTALLY agree with this article. What matters to me is comfortable, light and concealable, fast to get into point shoot status and reliable, reliable, reliable.

  • Chaplain Ed Skiba October 12, 2011, 9:00 pm

    Great stuff Jim. I’ve been shooting for a lot of years but you reminded me to be more careful when a new shooter asks this question. Look forward to the next segment. Blessings.

  • Chuck Lankford October 12, 2011, 6:11 pm

    Good article!
    Do you feel a small handgun(9mm) with a larger projectile with lower FPS would work better than a semi-auto (CZ52) which is a 7.62 but at 1600fps??


  • Phil October 12, 2011, 6:05 pm

    Nice article! Although this strays from the main objective of the article (selecting a firearm), I would suggest some consideration in bullet selection, post firearm selection. A jacketed hollow point will perform considerably differently than a hard cast flat nose bullet. Would the author consider a second article, “Triggernometry – Choose Your Load!” after this series is complete?

  • Ed Rodriguez October 12, 2011, 5:42 pm

    Excellent aricle. You explained very well. It is a hard subject to explain to a novice shooter, without sounding to complex.

  • joe pond October 12, 2011, 4:58 pm

    Excellent article, question. if the outline of the but of the handle can be vaguely seen but not readily recognizable as a gun, does it count as concealment?

    • Administrator October 12, 2011, 5:15 pm

      usually that doesn’t matter.

    • Thomas October 12, 2011, 9:57 pm

      in the state I am in, RI. Concealed or not you still need a CCW permit. That is IF the AG deems you “in need” of one.

      • DaveGinOly October 31, 2013, 1:13 am

        As a native Rhode Islander, I feel your pain. I now live in Washington state, where open carry is legal. A good thing about it – if you’re a CCW holder out and about and you realize you left your permit at home, you can take the gun from concealment and carry it openly, and you’re OK!

  • Thomas October 12, 2011, 3:09 pm

    This is a very informative piece of information about purchasing the “right” firearm for self defense. Far too many people suggest firearms that “they” are used to using, Mr. Higginbotham on the other hand here suggested a variety of different firearms but I believe emphasized that the “perfect weapon” would be one that is A- comfortable for the user, B- controllable for the shooter and C- able to be legally concealed and has ease of deployment when needed. There are other variables that should be considered but those are the general ones that would be needed to make an informed position. Finally keep in mind, if you legally or illegally (some general law abiding citizens do because the sever restrictions in their state, not because they are intending to commit some other crime- it is because they feel the need to have another tool at their disposal for self preservation) that you (the shooter) will have to accept the consequences of your final actions. Ok I’m done yapping, everyone who reads this have a great day and SAFE shooting!

  • Lou Salseda October 12, 2011, 1:30 pm

    Thanks Jim! Good start for first time shooters looking to make a gun purchase. After 38 years in the business and former director of LAPD’s firearms training I still enjoy training new shooters. I started to do training in the LA area. I am a court expert for the use of lethal force and can appreciate your insights into stopping effectiveness after viewing 100s of autopsys. I will pass this article to my new shooters.

  • Jim Mansayagan October 12, 2011, 9:09 am

    Very informative…science of shooting. 2 Thumbs up!
    Pt. 2 pls.

  • JD Mak October 12, 2011, 8:09 am

    One of the better articles I’ve read on choosing a weapon. I’ll be forwarding this to my buddies. Looking forward to Part 2!

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